Thomas jeefeesoi matthews dali



T. J. M. DALY AND L. DALT 0N.

AUTOMATIC THERMOSTAT.

APPLICATION FILED APR. 30. 1919.

1,321,287. w Patented Nov. 11,1919.

I I WITNESSES 1 JJ' NEW/5's I: a x

I inp z ATTORNEYS useful Improvement erated thermostats.

' well known.

THOMAS JEFFERSON MATTHEWS DAL Y AND LAMAR DALTON, 01? LITTLE- ROCK, ARKANSAS. I

AUTOMATIC rnEnMos'rA'r.

Specificationof Letters Patent.

Patented Nov. 11, isl

Application filed April 30, 1919. Serial No. 293,631.

To all whom it may concern:

Be it known that we, THOMAS JEFFERSON MATTHEWS DALY and LAMAR DALTON, citizens of the United States, and residents of Little Rock, in thecounty of Pulaski and State of Arkansas, have invented a new and in Automatic Thermostats, of which the following is a specification. 7

Our invention relates to electrically op- -An important object of the invention is to provide a thermostat of the above mentioned character, which is wholly automatic in operation, and has three thermostatic elements, which are actuated by the change in temperature of a resistance coil, the change in temperature in the chamber to be heated, and the change in temperature of the atmosphere in the room or the like within which the chamber is located.

A further object of the invention is to provide a device of the abovementioned character which is of simple construction, and reliable in operation. A

Other objects and advantages of the invention will be apparent during the course of the following description,

In the accompanying drawings forming a part of this specification and in which like numerals are employed to designate like parts throughout the same,

Figure 1 is a side elevation'of a device embodying our invention,

Fig. 2 is a central vertical longitudinal sectional view through the same, and,

Fig. 3 is a transverse sectional view taken on line 3-3 of Fig. 2.

In the drawings, wherein for the purpose of illustration is shown a preferred embodiment of our invention, the numeral 5 designates an upper thermostatic element, embodying an upper strip 6, preferably formed of steel, and a lower strip 7 preferably formed of brass, these strips being securely bound together by solder or the like. as is The lower strip 7 of brass, when the element is heated has thehigher co-efficient of expansion and will therefore cause the thermostatic element 5 to move upupper end of wardly. This thermostatic element may be formed of any other suitable metals having difierent co-eiiicients of expansion. he thermostatic element 5 is carried by a sup port 8, which is apertured for receiving a bolt 9, carrying insulating sleeves 10, the support 8 being out of contact with the bolt 9 and therefore thoroughly insulated from all other portions of the apparatus. The bolt 9 is securedto a support plate 11, as shown.

Arranged beneath the thermostatic ele-- ment 5 a coacting thermostatic element 12, embodying an upper strip 13 of brass, and

,a lower strip 14 of steel, these strips being bound together in any suitable manner and preferably wrapped with a section of insulated copper wire 15. The thermostatic element 13 is carried by aresilient support 16,

apertured for receiving the bolt 9, as shown.

. The numeral 17 designates a third thermostatic element, including an inner brass tube 18, which is preferably perforated. At its lower end, this brass -tube has connection with a yoke 19, which is suitably attached to -the support 16, by solder or' the like, this yoke having no electrical connection or contact with the support 8.

Surrounding the brass tube 18 is an outer perforated tube 20, formed of steel, and having screw-threaded engagement within an opening 21 formed in the plate 11.

The numeral 22 designates a horizontal disk preferably formed of fiber, and having a central aperture 23, to tightly receive the the outer tube 20, so that the disk may be rigidly secured thereto. The disk 22 carries a dial 2%, equipped with a scale indicating temperature degrees. Y A metallic ea or bushing 25 is arranged upon the top 0 the tube 20, and receives the screw-threaded upper end of the tube 18, but has no screw-threaded engagement therewith, the'tube being slidable therein. A nut 26 has screw-threaded engagement with the upper end of the tube 18 and is rigidly secured to. a preferably fiber disk 27, equipped with a pointer 28, to travel in contact with the temperature scale.

It is I thus seen that by turningthe disk 27, the

tube 18 may be slightly raised or lowered,

to pern'ianently adjust the thermostatic elcment 5. This contact element is adapted to engage and disengage a contact element 31 carried by the thermostatic element 12, as shown. The numeral 32 designtes a wire ha"ng connection with a suitable source oi current and connected w h one end. ot the coil 29. This wire has resistance coil connected in series therewith. i-"i second resistance coil 34: is connected with one end of the coil 33, and the opposite end of the coil 3% is connected with'a wire having electrical connection with the thermostatic element 12, as shown. An electric pilot light 36 is preferably connected in shunt with the coil 34:.

In the use of the device, be arranged within the or the like, and attached to the top 37 thereof. it is thus seen that the thermostatic elements 5 and 12 are arranged within the incubator chamber, while the thermostatic element 17 is disposed outwardly of the same in the room containing the incubator. The wire has electrical connection with a suitable heating unit, arranged in the incubator chamber. Upon the increase of current, the coil 29 heats up, and when the temperature reaches a predetermined de gree, thermostatic element 5 moves upwardly and breaks the engagement between contacts 30 and 31. This connects coil 3st in series with coil 33 and cuts down the current fed to the heating unit. The increased temperature of the incubator chamber also causes the thermostatic element 12 to move down- Wardly, which shifts the contact 3 away from the contact 30. The increase in temperature in the room exteriorly of the incubatorchamber will cause the thermostatic element 17 to function and bodily move the thermostatic element 12 away from the thermostatic element 5. p

It is to be understood that the form of our invention herewith shown and described is to be taken as a preferred example of the same, and that various changes in the shape, size, and arrangement of parts may be resorted to without departingfrom the spirit of our invention or the scope of the subjoined claims.

the plate 11 may incubator chamber acted upon by heat to shift the Having thus described our invention, we claim:

1. A device of the character described, con'iprising a thermostatic element carrying a contact, a second thermostatic element arranged near the first named thermostatic element and carrying a contact to coact with the first named contact, a heating coil snrrounding the first named thermostatic ele ment, a circuit in connection with theheating coil and the second named thermostatic element, and a third thermostatic element to bodily shift the second thermostatic element toward and away from the first named thermostatic element.

2. A device of the character described, comprising a thermostatic element having a contact portion, a second thermostatic element carrying a coacting contact portion, a heating coil surrounding the first named thermostatic element and having one end thereof electrically connected with the same, a third thermostatic element arranged upon one side of the first and second named thermostatic elements and connected with the second named thermostatic element to bodily shift it toward and away from the first named thermostatic element, and a circuit connected with the heating coil and the second named thermostatic element.

3. A device of the character described, comprising a thermostatic element embodying a plurality of strips having diil'erent co-eiiicients of expansion whereby the element is adapted to move upwardly when acted upon by heat, a second thermostatic element arranged beneath the first named thermostatic element and formed of strips having different co-eflicients of expansion whereby the second named thernmstatic element is adapted to move downwardly when acted upon by heat, contacts carried by the thermostatic elements, a heating coil surrounding the first named thermostatic ele ment and having electrical connection with the contact thereof, a circuit connected with the heating coil and the second named thermostatic element, and a third thermostatic element connected with the second named thermostatic element and adapted when second thermostatic element downwardly.

at. A device of the character described, comprising a thermostatic element embodying a plurality of strips having difi'erent co-eiiicients of expansion whereby the element is adapted to move upwardly when acted upon by heat, a second thermostatic element arranged beneath the first named thermostatic element and formed of strips having different coefficients of expansion whereby the second named thermostatic element is adapted to move downwardly when acted upon by heat, contacts carried by the hermostatic elements, a heating coil suroundmg the first named thermostatic ele' nent and having; electrical connection with ;he contact thereof, a circuit connected with :he heating coil and the second named therrnostatic element, a third thermostatic element connected with the second named ther- 

